// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_CONTROLS_GLOW_HOVER_CONTROLLER_H_
#define UI_VIEWS_CONTROLS_GLOW_HOVER_CONTROLLER_H_

#include "base/macros.h"
#include "ui/gfx/animation/animation_delegate.h"
#include "ui/gfx/animation/slide_animation.h"
#include "ui/views/views_export.h"

namespace gfx {
class Canvas;
class ImageSkia;
class Point;
}

namespace views {

class View;

// GlowHoverController is responsible for drawing a hover effect as is used by
// the tabstrip. Typical usage:
//   OnMouseEntered() -> invoke Show().
//   OnMouseMoved()   -> invoke SetLocation().
//   OnMouseExited()  -> invoke Hide().
//   OnPaint()        -> if ShouldDraw() returns true invoke Draw().
// Internally GlowHoverController uses an animation to animate the glow and
// invokes SchedulePaint() back on the View as necessary.
class VIEWS_EXPORT GlowHoverController : public gfx::AnimationDelegate {
public:
    enum Style {
        SUBTLE,
        PRONOUNCED
    };

    explicit GlowHoverController(views::View* view);
    ~GlowHoverController() override;

    // Sets the AnimationContainer used by the animation.
    void SetAnimationContainer(gfx::AnimationContainer* container);

    // Sets the location of the hover, relative to the View passed to the
    // constructor.
    void SetLocation(const gfx::Point& location);

    const gfx::Point& location() const { return location_; }

    // Initiates showing the hover.
    void Show(Style style);

    // Hides the hover.
    void Hide();

    // Hides the hover immediately.
    void HideImmediately();

    // Returns the value of the animation.
    double GetAnimationValue() const;

    SkAlpha GetAlpha() const;

    // Returns true if there is something to be drawn. Use this instead of
    // invoking Draw() if creating |mask_image| is expensive.
    bool ShouldDraw() const;

    // gfx::AnimationDelegate overrides:
    void AnimationEnded(const gfx::Animation* animation) override;
    void AnimationProgressed(const gfx::Animation* animation) override;

private:
    // View we're drawing to.
    views::View* view_;

    // Opacity of the glow ramps up over time.
    gfx::SlideAnimation animation_;

    // Location of the glow, relative to view.
    gfx::Point location_;
    double opacity_scale_;

    DISALLOW_COPY_AND_ASSIGN(GlowHoverController);
};

} // namespace views

#endif // UI_VIEWS_CONTROLS_GLOW_HOVER_CONTROLLER_H_
